The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when to plant fennel is to look at the USDA zone info for Broomfield.

Planting Calendar for Fennel

Frost tolerance for fennel:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since fennel are very cold tolerant you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant fennel in Broomfield is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant fennel and expect a good harvest is probably September. You probably don't want to wait any later than that or else your fennel may not have a chance to grow to maturity. Starting your fennel indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Broomfield. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Broomfield is just an average the actual date of last frost will vary from year to year. Half of the time in Broomfield last frost occurs after April 15 so be sure to be ready to cover your fennel if you have a late frost.

USDA Zone Info for Broomfield

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Broomfield

You may be interested in your other planting guides for Broomfield.